U.N. Ambassador Susan Rice has had a tough week. At the U.N., Rice had to explain to the world why the Obama administration was part of a small minority voting against the Palestinian statehood bid. She's also been under attack as a potential secretary of state. And as NPR's Michele Kelemen reports, her critics seem to be growing in number.

MICHELE KELEMEN, BYLINE: Susan Rice is not your typical diplomat. She certainly doesn't mince words, especially when it comes to Russia and China blocking Security Council action on Syria.

AMBASSADOR SUSAN RICE: The United States is disgusted that a couple of members of this council continue to prevent us from fulfilling our sole purpose here.

KELEMEN: She's often described as tough and abrasive. But David Rothkopf, CEO of Foreign Policy magazine, says that shouldn't rule her out for the top job at the State Department.

DAVID ROTHKOPF: I don't know anybody who gets to the level she's gotten to who doesn't have those characteristics, and certainly a lot of the secretaries of state that we've had in the past have been known for those characteristics.

KELEMEN: Think James Baker or Henry Kissinger. Rothkopf, who worked with Rice in the Clinton administration, doesn't believe she should be blamed for the muddled messages this administration had on the deadly attack on the U.S. consulate in Benghazi, Libya, nor does he think the personal attacks on Rice are fair.

ROTHKOPF: Part of it is that different people have personal agendas. They'd like to see somebody else in the job, and I think some of it's sexism. I think some of it has to do with the fact that, you know, there is a certain way to behave that I think men get a lot more latitude with than women.

KELEMEN: If she's tapped as secretary, though, there is a fair debate to be had about her record at the U.N. She negotiated tough sanctions on Iran and North Korea, and one of her former colleagues says she had a virtuoso performance getting a strong resolution on Libya. A former State Department official who dealt with the U.N., Mark Lagon, also sees Libya as a high point of Rice's tenure.

MARK LAGON: One of the reasons why she's been so concerned with atrocities in places like Libya is because she was an official in the Clinton administration responsible for Africa when the Rwandan genocide occurred.

KELEMEN: It was a period Rice clearly regrets. She was emotional when she spoke at a U.N. Genocide Remembrance Day in 2009.

RICE: The memory of stepping around and over those corpses will remain the most searing reminder imaginable of what our work here must aim to prevent.

KELEMEN: But Lagon, who now teaches at Georgetown University, says Rice has since become too close with Rwanda's post-genocide president, Paul Kagame.

LAGON: She actually has been someone who's put the brakes on shining a spotlight on how Rwanda has backed atrocities in the Democratic Republic of Congo.

KELEMEN: Her aides say that is patently untrue, though it's a common criticism from human rights groups. Environmentalists are now raising concerns about the investments Rice and her husband have in Canadian companies involved in the Keystone XL pipeline. The next secretary of state will play a key role in deciding whether to move ahead with that project. Her spokesperson says in a statement that Ambassador Rice has complied with annual financial disclosure and ethics requirements and will continue to do so.

And while her detractors are many, Rice does have something going for her, says Aaron David Miller, vice president of the Woodrow Wilson Center: her relationship with President Obama.

AARON DAVID MILLER: You need somebody who's very close and of the likely suspects who have been on the list to replace Hillary Clinton, Susan Rice is clearly not only the most loyal, but the one who is likely to have the greatest sway with the president.

KELEMEN: People who have worked with her say Rice can be charming when needed and can throw an elbow when she has to, and that's another asset in this town. Michele Kelemen, NPR News, Washington. Transcript provided by NPR, Copyright NPR.